The present invention relates generally to devices for sorting documents on-edge and more particularly to document sorting devices which include a sorter section with diverters for diverting flats, such as larger sized postal envelopes, magazines and the like into selected receptacles.
Document processing systems are generally known which convey documents on-edge along a main document transport path and into a sorting section in which the documents may be selectively diverted or sorted according to predetermined criteria such as their particular mail zone destination. Such sorting sections typically have a single primary conveyor path generally defined at least in part by a rectilinear, vertically disposed run of a primary endless conveyor belt.
Sorter sections for sorting flats typically include one or more document diverter or sorter stations which are disposed along both sides of the length of the primary conveyor belt. The sorter stations may each include a secondary conveyor belt having a run inclined to the primary conveyor path, along which a document travels when diverted from the primary converter path. Such document sorter stations may employ a switching roller disposed transverse to the primary conveyor belt which is movable to push the primary belt in a direction to cause a document to deviate from the primary or main conveyor path to a secondary or branch route. Other diverter stations employ pivotally mounted diverter elements.
Also, conventional sorter sections for sorting standard sized envelopes include a plurality of receptacles or stacking bins into which documents are diverted. The plurality of bins are generally formed as a plurality of rows of bins such that one row of bins opposes another row of bins on either side of the single primary conveyor path. The single primary conveyor path is interposed between the rows of opposing bins and must typically transport documents for all of the bins. Each bin typically has a dedicated diverter gate. The diverter gates are typically controlled by a computer or other control mechanism which determines the appropriate bin into which a document should be diverted.
A problem arises with conventional sorter sections having a single primary path for diverting documents since they are typically designed to handle shorter letter sized documents. The pivotal diverters at each sorting section are generally small and bend the shorter letter sized documents from the single primary path to the secondary conveyor belts. However, flats such as magazines and longer, larger envelopes cannot typically be bent as readily as letter sized documents and therefore generally collide or jam in conventional diverter mechanisms.
Other known sorter sections, such as disclosed in U.S. Pat. No. 3,750,880, gang individual sorter sections together. However, these sorters require that each single primary path of each individual sorter section be dedicated to a set of staggeredly opposing bins on each side of the single primary path as generally described above. Again, such systems are typically unsuited to properly transport and sort flats for the reasons described above. Staggered bins may contribute to wasted floor space since an opposing bin must be positioned downstream from an adjacent bin instead of directly across therefrom. In addition, such systems typically require a separate diverter mechanism for each primary path to divert documents into the appropriate individual sorter section. This increases complexity in dual path sorters since a plurality of additional diverters must be controlled in addition to the diverter dedicated for each bin.
Although some sorter sections use longer secondary paths along the single primary path to accommodate flats, the sorting stations are generally positioned along one side of the primary path because of the requisite length and size of the secondary paths and supporting belts. This drastically reduces sorting capacity since bins are not efficiently positioned on both sides of the primary path as with conventional sorters used with standard letter sizes.